NOAA has a nationwide (in USA) network of numbers you can call to report any sightings, HERE
Here’s a few tips to help the authorities when you make the call:
– List exact location you found the animal. If tide is going out, mention where you think the animal may drift to.
– Look for any signs of injury which may of lead to death or injury. Don’t touch, pickup or take-in with you. Keep a distance, possibly take pics if available.
Here’s a harbor seal we spotted on the Strait of Juan de Fuca last weekend.